[OPENMP] Codegen for 'taskwait' directive.

Emit the following code for 'taskwait' directive within tied task:
call i32 @__kmpc_omp_taskwait(<loc>, i32 <thread_id>);
Differential Revision: http://reviews.llvm.org/D9245

llvm-svn: 235836

clang/lib/CodeGen/CGOpenMPRuntime.cpp

@@ -748,6 +748,14 @@ CGOpenMPRuntime::createRuntimeFunction(OpenMPRTLFunction Function) {
     RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_end_ordered");
     break;
   }
+  case OMPRTL__kmpc_omp_taskwait: {
+    // Build kmp_int32 __kmpc_omp_taskwait(ident_t *loc, kmp_int32 global_tid);
+    llvm::Type *TypeParams[] = {getIdentTyPointerTy(), CGM.Int32Ty};
+    llvm::FunctionType *FnTy =
+        llvm::FunctionType::get(CGM.Int32Ty, TypeParams, /*isVarArg=*/false);
+    RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_omp_taskwait");
+    break;
+  }
   }
   return RTLFn;
 }
@@ -2062,6 +2070,15 @@ void CGOpenMPRuntime::emitReduction(CodeGenFunction &CGF, SourceLocation Loc,
   CGF.EmitBlock(DefaultBB, /*IsFinished=*/true);
 }
 
+void CGOpenMPRuntime::emitTaskwaitCall(CodeGenFunction &CGF,
+                                       SourceLocation Loc) {
+  // Build call kmp_int32 __kmpc_omp_taskwait(ident_t *loc, kmp_int32
+  // global_tid);
+  llvm::Value *Args[] = {emitUpdateLocation(CGF, Loc), getThreadID(CGF, Loc)};
+  // Ignore return result until untied tasks are supported.
+  CGF.EmitRuntimeCall(createRuntimeFunction(OMPRTL__kmpc_omp_taskwait), Args);
+}
+
 void CGOpenMPRuntime::emitInlinedDirective(CodeGenFunction &CGF,
                                            const RegionCodeGenTy &CodeGen) {
   InlinedOpenMPRegionRAII Region(CGF, CodeGen);

clang/lib/CodeGen/CGOpenMPRuntime.h

@@ -128,6 +128,9 @@ private:
     OMPRTL__kmpc_ordered,
     // Call to void __kmpc_end_ordered(ident_t *loc, kmp_int32 global_tid);
     OMPRTL__kmpc_end_ordered,
+    // Call to kmp_int32 __kmpc_omp_taskwait(ident_t *loc, kmp_int32
+    // global_tid);
+    OMPRTL__kmpc_omp_taskwait,
   };
 
   /// \brief Values for bit flags used in the ident_t to describe the fields.
@@ -602,6 +605,9 @@ public:
                              ArrayRef<const Expr *> RHSExprs,
                              ArrayRef<const Expr *> ReductionOps,
                              bool WithNowait);
+
+  /// \brief Emit code for 'taskwait' directive.
+  virtual void emitTaskwaitCall(CodeGenFunction &CGF, SourceLocation Loc);
 };
 
 } // namespace CodeGen

clang/lib/CodeGen/CGStmtOpenMP.cpp

@@ -1435,8 +1435,8 @@ void CodeGenFunction::EmitOMPBarrierDirective(const OMPBarrierDirective &S) {
   CGM.getOpenMPRuntime().emitBarrierCall(*this, S.getLocStart(), OMPD_barrier);
 }
 
-void CodeGenFunction::EmitOMPTaskwaitDirective(const OMPTaskwaitDirective &) {
-  llvm_unreachable("CodeGen for 'omp taskwait' is not supported yet.");
+void CodeGenFunction::EmitOMPTaskwaitDirective(const OMPTaskwaitDirective &S) {
+  CGM.getOpenMPRuntime().emitTaskwaitCall(*this, S.getLocStart());
 }
 
 void CodeGenFunction::EmitOMPFlushDirective(const OMPFlushDirective &S) {

clang/test/OpenMP/taskwait_codegen.cpp

@@ -0,0 +1,31 @@
+// RUN: %clang_cc1 -verify -triple x86_64-apple-darwin10 -fopenmp=libiomp5 -x c++ -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -fopenmp=libiomp5 -x c++ -triple x86_64-apple-darwin10 -emit-pch -o %t %s
+// RUN: %clang_cc1 -fopenmp=libiomp5 -x c++ -triple x86_64-apple-darwin10 -include-pch %t -verify %s -emit-llvm -o - | FileCheck %s
+// expected-no-diagnostics
+
+#ifndef HEADER
+#define HEADER
+
+void foo() {}
+
+template <class T>
+T tmain(T argc) {
+  static T a;
+#pragma omp taskwait
+  return a + argc;
+}
+int main(int argc, char **argv) {
+#pragma omp taskwait
+  return tmain(argc);
+}
+
+// CHECK-LABEL: @main
+// CHECK: [[GTID:%.+]] = call i32 @__kmpc_global_thread_num(%{{.+}}* @{{.+}})
+// CHECK: call i32 @__kmpc_omp_taskwait(%{{.+}}* @{{.+}}, i32 [[GTID]])
+
+// CHECK-LABEL: tmain
+// CHECK: [[GTID:%.+]] = call i32 @__kmpc_global_thread_num(%{{.+}}* @{{.+}})
+// CHECK: call i32 @__kmpc_omp_taskwait(%{{.+}}* @{{.+}}, i32 [[GTID]])
+
+
+#endif